Vehicles generate power both to propel the vehicle and to supply various electrical loads in the vehicle. Types of power systems include a conventional powertrain including an internal-combustion engine coupled to a transmission that transfers rotational motion to wheels; an electric powertrain including batteries, an electric motor, and a transmission that transfers rotational motion to the wheels; and a hybrid powertrain including elements of the conventional powertrain and the electric powertrain. In vehicles with conventional powertrains, an alternator transforms rotational kinetic energy from the engine into electrical energy for the electrical loads. In all-electric and hybrid-electric vehicles, a DC/DC converter may convert between high-voltage electrical energy for propelling the vehicle and low-voltage energy for the electrical loads.